Automatically collapsible inside form



2 Sheets-Sheet 2 wA/ANQ //v vav TokS COLIN/YIJTCH/Ns A'rroewzrs C. HUTCHINS ET AL AUTOMATICALLY COLLAPSIBLE INSIDE FORM 5: 6454/65/10 rc/mvs July 23, 1957 Filed Aprii 17, 1953 vii!" II-Ill United States Fatent AUTOMATICALLY COLLAPSIBLE INSIDE FORD/I Colin Hutchins and Glen Burrows Hutchins, Leamington, Ontario, Canada; said Colin Hutchins assignor to said Glen B. Hutchins Application April 17, 1953, Serial No. 349,458

Claims priority, application Canada April 24, 1952 3 Claims. (Cl. 25-130) This invention relates to an automatically collapsible inside form which is to be used in the casting of rectangular concrete articles having a rectangular base, such as septic tanks, catch basins, and burial vaults. It is fairly well established in the art to which this invention the side walls of the two forms the concrete which is to make up the rectangular bottom of the article. United States Patents 1,007,452 (P. V. Kornefiel et al., October 31, 1911) and 2,543,892 (I. H. K. Carpenter, March 6, 1951) constitute representatives of the prior art,

and teach the desirabilityof pouring in the inverted posi-- tion.

So far as we have been able to ascertain from diligent searching, there have been no prior proposals in this field which provide for automatic inward collapsing of the inside form as the cast concrete article is drawn upwardly away therefrom. Since it is simpler to dismantle and withdraw an outside form from a cast concrete article than it is an inside form, it will be appreciated that it would be advantageous to have the inside form automatically collapse as the outside form and the article are withdrawn upwardly therefrom, since it will be realized that it would then be a simple matter to turn the article to the position it would normally occupyin use and then remove the outside form. The inside forms of the prior art must be mechanically manipulated before they can be knocked down, so that there is no question of the article being raised away from an inside form which automatically collapses inwardly. Thus, for example, in the above-mentioned United States Patent 1,007,452, the inside form is only removable from the interior of the cast article after inverting the article from the as cast position, and operating a number of turn-buckle structures arranged in the four corners of the inside form; while in the case of the abovementioned United States Patent 2,543,892, the cast tank with the inner form still in place is inverted and seated in the storage place, whereupon certain locks which are located in each of the four corners of the inside form are released, after which the inner form is withdrawn upwardly away from the cast article and returned to the pouring platform. We appreciate that there have been prior proposals, for example, in United States Patent 2,228,123 (B. D. McMurray, January 7, 1941), in which both the outer form and the concrete article have been withdrawn upwardly after the casting of the article, 1eaving the inside form in its original position on the casting platform. However, this has only been possible in cases where there has been a substantial inward tapering of the side and end walls of the inside form, so that inward collapsing is not required of the form.

The inside form of our invention may be generally defined as comprising a solid rectangular base; four generally vertically arranged trapezoidal centre-pieces of equal height hingedly connected to said base, said centrepieces tapering upwardly; and four L-shaped cornerpieces of the same height as said centre-pieces movably connected to said centre-pieces, said corner-pieces having end walls which taper downwardly at the same rate as the adjacent end of each adjacent centre-piece; said four centre-pieces and said four corner-pieces constituting a complete rectangular wall when the bottom edges of all eight pieces are flush with the upper surface of said base; the hinging of said centre-pieces to said base and the movable connection of said corner-pieces to said centre-pieces being such that the corner-pieces, when a lifting force is applied thereto, will travel both inwardly and upwardly, whilst said centre-pieces will tip inwardly, so that a rectangular concrete article cast around said inside form may be raised away therefrom with facility.

An embodiment of our invention has been shown in the attached drawings in which:

Figure 1 is a top perspective view of an inside form and outside form set up thereabout,

Figure2 is a detailed perspective view of one corner of the inside form as seen from the interior thereof,

about one-quarter of the form being shown, and

Figure 3 is a vertical transverse section taken through one of the walls of the two forms after pouring.

Referring to the drawings, reference numeral 10 indicates a rectangular base member. Four generally vertically arranged trapezoidal centre-pieces 11 of equal height are hingedly connected to the base 10 by hinges 12. These centre-pieces are located midway along each -side and end of the rectangular base 10. Each of the The hinging of the centre-pieces 11 to the base 10 and Q the connection of the corner-pieces 13 to the centrepieces 11 is such that the corner-pieces, when a lifting force is applied thereto, will travel both inwardly and upwardly, while the centre-pieces 11 will tip slightly inwardly. With this arrangement, when a rectangular concrete article with a rectangular base is cast in an inverted position around the inside form, the cast article may be raised away from the inside form with facility. If the cast concrete article were not freed. from the corner-pieces and the centre-pieces as it was raised, it would exert a draggingeffect on the corner-pieces and raise the latter somewhat (or carry the whole inside form away from the pouring station) when the article was withdrawn upwardly. However, with the inside form of our invention, as the corner-pieces 13 are raised, they not only travel upwardly, but also travel inwardly, i. e.,

- away from the concrete article, freeing it. At the same time, the centre-pieces 11 tip slightly inwardly and away from the cast concrete article being withdrawn.

The manner in which the corner-pieces 13 are movably connected to the adjacent centre-pieces 11 will now be described. Each corner-piece 13 is movably connected to the two centre-pieces 11 adjacent its ends by a pair of generally parallel, vertically spaced and vertically aligned arms 18. One end of each arm 18 is pivotally connected to centre-piece 11 as indicated at 19. The other end of each arm 18 is pivotally connected to one of the corner members 13, as indicated at 20. Prefer- Patented July 23, 1951 ably, two vertically spaced and vertically aligned projections 21 extend inwardly from the inner face of each of said centre-pieces, and the two upper and the two lower arms 18 associated with eachcentre-piece11- are pivotally connected to the upper and-lower projections 21, respectively. 7 I

The inside form of our invention preferably/includes a vertical post 16 which is rigidly secured to the rectan-t gular base 10 at its centre the post 16 to each of the. corner-pieces 13. Each arm 17 is pivotally attached at its opposite ends to the post 16 (as indicated at 17A in. Figure l) and .tolone of the corner-pieces 13 (as vindicatedat-17B in'Figure-2-) We prefer to provide the above-describedlarrangernent to prevent any tendency for the form to collapse inwardlyi as the concrete is poured. V

The use to which the inside form of: ourinyentiommay be put will now :be described. a The inside form is. placed on a pouring platform. The corner-pieces 13 Q. are tar-t ranged with their. bottom edges fiushv with the upper surface of the base .10, tso that the fourccentrepieces 1 1 and the four corner-pieces:l3vtogether constitute a complete rectangular wall. A suitablerectangular outside form of collapsible constructionis. then arranged around the inside form. Such a form is shown inHFig.

1, and is partially shown in Figure 3. This outsidelformis made up of two -L-shaped'pieces 22 and23, each of which consists of a side and an end piece. The outside form is somewhat taller thanttheinside form ,andis provided with an inwardly extending lip 24 rigidly. secured to its base. The lip 24 is of the same vcrtical depthas rectangular base 10 of the insideform and extends inwardly-to meetthe base on all its four sides,vi. e. lip 24 continues along the bases of both the -L-shaped pieces 22 and 23. V a

When thetwo formshave been positioned, they cooperate to provide a rectangular well therebetweenfl A-' solid platform is placed on topof the inside formto" completely cover the latter.- Concrete 25 is then poured on top of the platform and into the rectangular wellbetween the two forms until the well has been completely filled, and a concrete layer (of the thickness desired forand the cast article are lifted away from the inside form, which remainson the pouring platforms Therim ;24- on the base of the outside form ensures the removal oft the cast article with the outside form.v The'outsideforrn andthe cast. article are: inverted and placed in vsome-: storage point, and 1 the outside formis collapsed; away 1 from the cast article.

The outside form and the cast concrete anticle-maybe withdrawn upwardly away from the'inside form with facility, since, if there is-any bindinglbetween the article and the .outside faces of one ,or more of the corner-. pieces 13, thisbinding'will result in a raising of the corner-pieces.- As the corner-pieces 13 are raised,they1- are forced to travel bothinwardly as well as upwardly, due to the nature of their connection to the centre-pieces Anv arm 17 extends from 11. This inward travel, being away from the concrete article, assures freeing of the article with respect to the form. Furthermore, as has been mentioned above, as the corner-pieces move upwardly and inwardly, the centrepieces 11 are constrained to tip inwardly, so that they, too, will be freed from the portions of the concrete article which face them.

What I claim as my invention is:

1. An automatically collapsible ,inside form for the casting of concrete articles of rectangular form which comprises a solid rectangular base; four generally vertically arranged trapezoidal centre-pieces of equal height hingedlyjconnected -to;said base, said centre-pieces tapering upwardly; and four L-shaped corner-pieces of the same height as said centre-pieces movably connected to a said centre-pieces, a vertical post rigidly secured to said rectangular base at its centre point and an arm extending from said post; to eachof said corner-pieces,; s aid arms being pivotally attached at: their ends to said post and to said corner-pieces, said corner-pieces having end walls which -taper downwardly at the same rateas the adjacent end of each adjacent centre-piece; said four, centre-pieces and saidfour corner pieces constituting-m,

complete rectangular wall whenr the bottom edges of all eight pieces are flush with the upper surface of-said base;- the hinging of said centre-piecesto said base and the movable connection of said corner-pieces'to'said centre-- pieces being such that the corner-pieces, when a lifting force is applied thereto, will be'forced to travel both},

inwardly and upwardly,-whilst said centre-pieces will ;be constrained to tip inwardly, so that a rectangularcom cretearticle cast around said inside'form may be raised away therefrom with facility.

2. An automatically collapsible inside form as defined in claim 1, in which each corner-piece is connected to the centre-piece adjacent each end thereof by a pair of generally parallel vertically spaced arms-,one end of each" of said arms being pivotally connected to a centre-pieceand the other endof each'of said-arms being pivotallyconnected to a corner-piece, and in which twovertically spaced and vertically aligned projections extend inwardly 1 from the'inner faceof each of said centre-pieces,',and I said projections constitute the points of pivotal connection ofsaid arms to said-centre-pieces.

3. An automatically collapsibleinside' formas defined I in claim '1, in which each corner-piece isconnected to 'the centre-piece adjacent each end-thereof by a pair, of--. generally parallel vertically spaced arms, oneend of each:v of said arms being pivotally connected to a centre-piece and the-other end of each of said armsbeingflpivotally connected to a corner-piece;

References Cited in the He of .this' patent UNITED STATES PATENTS 

